After a very mild start, cold, stormy weather is raging across much of the contiguous United States.
Boosted by record-cold air and driven by back-to-back storms, the mid-January snow cover is the most extensive in two decades of modern data. The change to this wintry pattern has been dramatic and swift. Around Christmas, the nation’s snow cover hovered at record lows and December would close as the warmest on record.
As snow has blanketed large parts of the nation, repeated invasions of Arctic air have stoked a jump in Great Lakes ice, which hovered at record-low levels in early January.
Another blast of cold, along with a storm sweeping the northern tier, will tighten winter’s grip through the weekend. But then a major thaw is forecast next week.
Record snow cover for the date
More than 56 percent of the contiguous United States is currently covered in snow, following a pair of storms. The first swept from the Plains to the Great Lakes last week. It was followed by a second system that produced a stripe of snow from the mid-South to the Northeast between Sunday and Tuesday. The snow cover extent Thursday surpasses the previous record of 53.7 percent on this date in 2018. Snow cover data dates to 2004.
After the record warmth in December, January has seen a sudden shift toward both colder and snowier weather. January’s countrywide average temperature is 1.2 degrees below average through mid-month, amid what’s historically the coldest part of winter. And it’s not only snow that’s expanding because of it.
Great Lakes ice growth
After historic lows, Great Lakes ice cover has pulled off a rapid resurgence over the past week as Arctic air settled into the region.
Ice coverage had climbed to 10 percent as of Wednesday. Just a week ago, the coverage averaged over the lakes was only 1 percent.
While the ice has experienced a dramatic turnaround, mostly given the tiny amount to start, the coverage is still well below the average of 22 percent. Ice cover could grow through the weekend but then may pause or even recede with the anticipated thaw next week.
Advertisement
Annual ice cover typically peaks between mid-February and early March at a little above 4o percent. Maximum ice cover is highly variable year to year but is trending downward as winter temperatures rise because of human-caused climate change.
Share this articleShareLake-effect snow machine on full blast
The lack of ice over the Great Lakes has been a boon for lake-effect snows, which require open water. Often, these snows begin to shut down by this point in the season as ice covers the lakes. But with so little ice this year, the open water has served as a vast supply of moisture as cold winds sweep over the lakes, and snowfall on downwind shores has been abundant.
Warnings for lake-effect snows continue through Thursday evening for locations downwind of lakes Ontario and Erie, with another 12 to 22 inches expected amid hourly rates potentially as high as 3 or 4 inches per hour.
Advertisement
Into the weekend, another round of substantial lake-effect snow is anticipated as a reinforcing shot of Arctic air dives toward the eastern United States.
Winter storm warnings take effect Thursday night and last until Saturday downwind of Lake Michigan. As much as a foot or more of snow is forecast in parts of southeast Michigan and northern Indiana.
Significant snowfall is also forecast in the snowbelts of Lake Superior, and additional heavy lake-effect bands probably will target the eastern lakes into the weekend, on top of copious snow that has fallen in the past week.
In Buffalo, 27.2 inches had officially fallen through Wednesday, with most of the snowbelt areas downwind of the lakes picking up a foot or two during the same period. A few areas just south of Buffalo posted totals over 60 inches between Sunday and Wednesday.
As milder weather returns next week, many of the recent trends toward more cold, snow and ice will reverse in much of the central and eastern United States.
ncG1vNJzZmivp6x7uK3SoaCnn6Sku7G70q1lnKedZMSmrdOhnKtnYmV%2FdXuPamZqcF%2Bou7DDjJymr52iYr%2Bmr86rm2afopqutXnLmqKeq12esKZ7